Author Topic: Grayscale Engravings done with T2  (Read 11580 times)

nehal

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Grayscale Engravings done with T2
« on: July 03, 2017, 12:05:43 PM »
Here are some of the grayscale engravings done using T2. I had some time experementing. I will be posting images with settings.
Setup:
Eleksmaker A3
Mana SE board
2300mw TTL laser

This was the image used as a test image to get proper calibration/settings.

Engravings are done on mdf, cardboard. I will be updating this thread with many other materials. My initial results were from charcoal like to very light.

Here is one of the tests.
Speed: 3400
Res: 0.15
Diagonal engraving
Power: 25-255

Shades look good. But small details are shaky. So either I have to stabilize the engraver mechanically or lower the speed and power to compensate it.

Test2
Speed:2800
Res:0.15
Power: 25-210


I will be using above settings for most of the engravings on mdf.

Let's start with cardboard. It's tricky to engrave as it quickly turns to charcoal at power abrove 110 even at high speeds.

Speed: 3200
Power:30-100
Res:0.1


Speed: 3200
Power: 20-65
Res:0.1


Speed: 3200
Power: 25-100
Res: 0.1


Let's move to mdf.
Speed: 3400
Res:0.15
Power: 20-255
Horizontal


Speed: 3400
Res:0.15
Power: 20-255
Horizontal



nehal

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Re: Grayscale Engravings done with T2
« Reply #1 on: July 03, 2017, 12:29:40 PM »
Speed: 2800
Power: 25-210
Res: 0.15
















Dithering
Power: 200
Speed: 3000
Res: 0.1


nehal

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Re: Grayscale Engravings done with T2
« Reply #2 on: July 03, 2017, 12:33:46 PM »
More images coming up. I will be testing on birch ply and other wood, mirror, glass, acrylic etc when I get time. Please post your comments and suggestions.
« Last Edit: July 03, 2017, 10:28:02 PM by nehal »

Zax

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Re: Grayscale Engravings done with T2
« Reply #3 on: July 03, 2017, 12:45:56 PM »
I would say you're getting a tiny amount of backlash, possibly due to the speed or belts but still very good results. Nice job!

I like your test file too, well done.

Look forward to seeing your experimentation with other materials.

nehal

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Re: Grayscale Engravings done with T2
« Reply #4 on: July 03, 2017, 10:21:37 PM »
Thank you Zax. The test file is from thingiverse. Should I tighten the belts?

I have a suggestion for T2 related to engraving. For 45deg engraving, the starting point is a tiny dot. So at the begining of engraving, for about 5 second or so, laser moves like crazy due to small area. My suggestion is, can you add extra few mm to gcode so that after the edge of the image, the laser turns off and it keeps on moving for another3-5mm, comes back to the point, turns on again and so on. This should act as "software compensation" to any artifacts around any edge of the image due to rapid change in direction. Not just to the starting area, but it can be implemented to entire image to its all four edges.
« Last Edit: July 03, 2017, 10:26:59 PM by nehal »

Zax

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Re: Grayscale Engravings done with T2
« Reply #5 on: July 04, 2017, 04:17:38 AM »
Yes, I think you could tighten the belts a little to see if it helps. Your text should be cleaner, try disabling bi-directional as that's an easy way to see if it's backlash.

You can enable over-scan, but it isn't anywhere near 3-5 mm. If I remember correctly it's 2X the resolution so if you are using 0.1 it's only 0.2 mm.

The negative with over-scan is explained in my documentation, but basically you need to ensure the 0,0 (start point) isn't at the machine 0,0 or it would potentially hit the limits and it also slightly increases the image size and shifts center. At 0.2 mm it isn't noticeable, but that's why I didn't do 3-5 mm.

On my machine with home switches you can start it using over-scan at machine 0,0 as there's enough travel (since at home Grbl pulls away a little). Not all machines work like this so I have to design something for everyone.

The easiest way to achieve what you are suggesting is to add a white space border to the image and not enable rapid skip blank. Essentially the same as the software doing it, but then you have control and a known image size / center etc.

I may be able to do something else though to prevent the "spot", let me give it some thought.
« Last Edit: July 04, 2017, 04:19:43 AM by Zax »

nehal

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Re: Grayscale Engravings done with T2
« Reply #6 on: July 04, 2017, 07:27:30 AM »
Thank you Zax. White border is nice idea. I will try it to see the difference. Can it be implemented as an optional feature in T2?

Zax

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Re: Grayscale Engravings done with T2
« Reply #7 on: July 04, 2017, 09:20:02 AM »
It could, I will experiment and see what works best.

nehal

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Re: Grayscale Engravings done with T2
« Reply #8 on: July 06, 2017, 07:11:33 AM »
Adding white space did the trick.  Added 3 mm around all the edges and the visible backlash artifacts are gone.
Feature like this in T2 will help greatly. Also things like sharpening image, rgb channel control will be very helpful for better contrast.

Here is the image done with added whitespace.


Zax

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Re: Grayscale Engravings done with T2
« Reply #9 on: July 06, 2017, 08:13:01 AM »
That's a challenging image with all the windows (lines), looks fantastic. Great job!

Usually brightness, contrast and gamma are sufficient, but I could add individual RGB channel controls and sharpening. I will add it to my list, probably lower priority as I typically use Photoshop and prepare the images before importing (that way you can clean up backgrounds or noise much better).


nehal

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Re: Grayscale Engravings done with T2
« Reply #10 on: July 06, 2017, 09:21:37 AM »
Thank you Zax. The image is 110mm width, engraving bigger will bring out more detail.

I used inkscape for white space and editing rgb when needed. Please add "add white space" feature to T2 , as it's very helpful for mechanically under optimized systems. So that it can be added on the go.
« Last Edit: July 06, 2017, 10:25:43 AM by nehal »

Zax

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Re: Grayscale Engravings done with T2
« Reply #11 on: July 06, 2017, 11:12:29 AM »
It's on the list.

johnboyjr33

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Re: Grayscale Engravings done with T2
« Reply #12 on: July 10, 2017, 02:00:37 PM »
i just got the same laser i think it turned out great for you. can you share all the settings you used i am trying to learn how to use this. most of the time i get to light or to dark of an image but i seem to be getting closer. thanks

nehal

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Re: Grayscale Engravings done with T2
« Reply #13 on: July 11, 2017, 07:27:50 AM »
Start with the engraving test image attached in first post. Import it using 0.1 resolution, to get closest to it's actual dimensions. Then you can change to around 0.15.

Second, what material are you trying to engrave? Not every material has linear response to laser. What board do you have? Do you have your laser wired for TTL?

Birch ply and mdf have good linear response to laser. I am yet to try different wood and other materials. Considering TTL setup, here is what to try.

0.15 resolution is good balance for quality vs time and produce no overlaping. Use diagonal engraving. Load the test image. Try speed 1000-3500. Narrow down the range. If too light, decrease speed, too dark then go faster, until you get proper shades from dark to light. Then try these settings on any other image. Also check laser focus.

Set lower S value just below the point your laser start to engrave.

johnboyjr33

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Re: Grayscale Engravings done with T2
« Reply #14 on: July 11, 2017, 10:29:43 AM »
Ok thanks I will try all that stuff